Polymers, including homopolymers and copolymers, which are both biocompatible and absorbable in vivo are well known in the art. Such polymers are typically used to manufacture medical devices which are implanted in body tissue and absorb over time. Examples of such medical devices manufactured from these absorbable biocompatible polymers include suture anchor devices, sutures, staples, surgical tacks, clips, plates and screws, drug delivery devices, adhesion prevention films and foams, and tissue adhesives, etc.
Absorbable, biocompatible polymers useful for manufacturing medical devices include both natural and synthetic polymers. Natural polymers include cat gut, cellulose derivatives, collagen, etc. Synthetic polymers may consist of various aliphatic polyesters, polyanhydrides, poly(orthoester)s, and the like. Natural polymers typically absorb by an enzymatic degradation process in the body, while synthetic absorbable polymers typically degrade by a hydrolytic mechanism.
Synthetic absorbable polymers which are typically used to manufacture medical devices include homopolymers such as poly(glycolide), poly(lactide), poly(e-caprolactone), poly(trimethylene carbonate) and poly(p-dioxanone) and copolymers such as poly(lactide-co-glycolide), poly(e-caprolactone-co-glycolide), and poly(glycolide-co-trimethylene carbonate). The polymers may be statistically random copolymers, segmented copolymers, block copolymers, or graft copolymers. It is also known that both homopolymers and copolymers can be used to prepare blends.
U.S. Pat. Nos. 3,997,512, 4,048,256, 4,076,798, 4,095,600, 4,118,470, and 4,122,129, describe several biocompatible, absorbable, low Tg, aliphatic polyesters known as poly(alkylene diglycolate)s. These polymers are prepared from the polycondensation of diglycolic acid and glycols such as ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and the like. These film forming, non-branched, non-crosslinked, linear polymers have found use in drug delivery.
However, there is a constant need in this art for new polymer compositions having improved properties when formed into medical devices. For example, there is a great need for soft, flexible, elastomeric, low melting or liquid polymers for use as tissue adhesives and sealants, bone waxes, cartilage replacements, adhesion prevention barriers, and soft tissue augmentation fillers.
Consequently, for applications such as bone waxes or cartilage replacement, it would be highly desirable to have a polymeric material having characteristics such as pliability, and elasticity as found in highly branched or crosslinked gels.
Furthermore, materials used for biomedical applications such as defect fillers, and tissue adhesives and sealants require characteristics such as hydrophilicity, ease of application (i.e., low viscosity liquid) and quick setting times (i.e., water or light curing).
Accordingly, what is needed in this art are novel polymeric materials which are liquid or low melting, soft, flexible, and elastomeric.
Surprisingly, we have discovered that by selecting appropriate combinations of poly(alkylene diglycolate) homo- or co-polymers, or by post-polymerizing/crosslinking pendant acrylate groups on poly(alkylene diglycolate)s, or by preparing copolymers or blends of poly(alkylene diglycolate)s with aliphatic polyesters such as poly(e-caprolactone), poly(p-dioxanone), and poly(trimethylene carbonate), materials with a wide range of unique physical characteristics, such as those described above, useful as tissue adhesives and sealants, bone wax, cartilage replacement, adhesion prevention barriers, and soft tissue augmentation fillers can be prepared.